The ultimate goal of this program is to determine how histone lysine and arginine methyl marks are installed, recognized, interpreted and possibly removed on gene promoters for the purpose of regulating or modulating critical biological processes that are strongly involved in cancer development, such as progenitor differentiation versus proliferation in hematopoietic malignancies. Notably, both the H3K4me "writer", MLL, and the "eraser", JARID1, contain several PHD fingers that "read" H3K4me marks, and the dysregulation of either of these enzymes causes blood cancers in humans. The "reader" that recognizes histone arginine methylation marks will be identified using approaches that were proven successful for identified H3K4me binding modules, PHD fingers (Allis lab). Structural analyses (Patel lab) will yield valuable insights into how these marks are "read" by key effectors to bring about downstream events. A complete understanding of these mechanisms will require access to defined chromatin with these modifications pre- installed in a controlled, homogeneous manner (Muir lab). Thus, a key component of this program is the creation of a research infrastructure based on what we term "designer chromatin" - that is, chemically defined mono-nucleosomes and nucleosome arrays in which one or more histone PTMs are incorporated site-specifically. We propose to build a biochemical resource consisting of a library of "designer chromatin" for use throughout this collaborative program. Emphasis will be placed on in vitro transcription assays as a functional readout for histone lysine/arginine methylations, as co-activators such as MLL, CARM1 and PRMT1, catalyze robust transcription via methylation on target lysine/arginine sites using a pure transcription system with defined chromatin templates of target promoters (Roeder lab). PUBLIC HEALTH RELEVANCE: The broad focus of this research program is the epigenetic regulation of transcription and how this relates to cancer, and our program is rooted in the idea that an indexing system exists for our genome, or what has been referred to as a "histone or epigenetic code" that represents a fundamental regulatory mechanism that operates outside of the DNA itself. We favor the view that deregulation of chromatin-templated processes leads to far-reaching consequences for cell fate decisions in normal and pathological development, especially cancers, and our specific goal is to understand the underlying molecular mechanisms of this "code" as it relates to the regulation of gene transcription. Biochemical and biophysical approaches will be used in conjunction with chemically defined chromatin to explore the interplay between the post-translational modification (PTM) of histones and chromatin structure and function.